Diastereoselective Spirocyclization of C-(Alkyloxycarbonyl)formimines of 2-Substituted 1HIndole-3-ethanamines (= Tryptamines): Basic Studies. 5th Communication on Indoles, Indolenines, and Indolines

✍ Scribed by Ralf Freund; Siavosh Mahboobi; Klaus Noack; Peter Schonhölzer; Karl Bernauer

• Book ID: 102858249
• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: German
• Weight: 955 KB
• Volume: 73
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19900730224

✦ Synopsis

OMe

H OMe ') 4th communication: [I] .

H COOMe (2'S,3R)-20 23 (-)-Tabersonine

The imine 15B afforded, with good diastereoselectivity, the crystalline (2'R,3S)-tricycle 19B. In the case of 15D, a crystalline mixture of diastereoisomers 19D was obtained. With the imine 17B, again formation of the (2'R,3S)-tricycle 21B is favored, but with poor and variable selectivity. A (3S)-spirotricycle 22B is the main product starting from the imine 1SB. From lSA, a mixture of two diastereoisomers 22A was obtained (39% de in favor of the (3R)-isomer). 3, Woodward and coworkers run the reaction 3 -+ 4 in pyridine at r.t. ') Separate signals of the major diastereoisomer are marked by *.